Applications of Cosmogenic Isotopes as Atmospheric Tracers

Abstract

Earth’s atmosphere is constantly bombarded by cosmic-ray particles and the interaction of these cosmic-ray particles with the target nuclei continuously produce a suite of radionuclides which serve as powerful tracers to identify and quantify several atmospheric processes. These include sources and transport and mixing of air masses, exchange of air-masses between various layers of the atmosphere (e.g., stratosphere–troposphere exchange, STE), residence times of atmospheric gases, removal rates and residence times of atmospheric pollutants to name a few. Combining the cosmogenic radionuclides with other naturally-occurring (primarily daughter products of 222Rn) and anthropogenic (mainly derived from nuclear weapons testing) radionuclides, have significantly aided to improve our understanding of the time scales involved with the interhemispheric exchange, meridional mixing and cross-Equator mixing as well as residence time of tropospheric aerosols. In this article, we review some of the key applications of cosmogenic radionuclides tracers in the atmosphere.